Recently, research and development of electrophotographic photosensitive members (organic electrophotographic photosensitive members) using an organic photoconductive material have been performed actively.
The electrophotographic photosensitive member basically includes a support and a photosensitive layer formed on the support. Actually, however, in order to cover defects of the surface of the support, protect the photosensitive layer from electrical damage, improve charging properties, and improve charge injection prohibiting properties from the support to the photosensitive layer, a variety of layers is often provided between the support and the photosensitive layer.
Among the layers provided between the support and the photosensitive layer, as a layer provided to cover defects of the surface of the support, a layer containing metal oxide particles is known. The layer containing a metal oxide particle usually has a higher conductivity than that of the layer containing no metal oxide particle (for example, volume resistivity of 1.0×108 to 5.0×1012 Ω·cm). Thus, even if the film thickness of the layer is increased, residual potential is hardly increased at the time of forming an image, and dark potential and bright potential hardly fluctuate. For this reason, the defects of the surface of the support are easily covered. Such a highly conductive layer (hereinafter, referred to as a “conductive layer (electrically conductive layer)”) is provided between the support and the photosensitive layer to cover the defects of the surface of the support. Thereby, the tolerable range of the defects of the surface of the support is wider. As a result, the tolerable range of the support to be used is significantly wider, leading to an advantage in that productivity of the electrophotographic photosensitive member can be improved.
Patent Literature 1 discloses a technique for containing a titanium oxide particle coated with tin oxide doped with phosphorus, tungsten, or fluorine in a conductive layer provided between a support and a photosensitive layer.
Patent Literature 2 discloses a technique for containing a titanium oxide particle coated with tin oxide doped with phosphorus or tungsten in a conductive layer provided between a support and a photosensitive layer.